1. Field of the Invention
The present invention relates to a steering column for a vehicle. In more particular, the present invention relates to a steering column for a vehicle which is configured to prevent loads transmitted to the steering column from being concentrated to a part of the steering column, to uniformize the distribution of operation force of an adjusting lever, and to increase the rigidity of the entirety of the steering column while maintaining the bearing forces of an upper tube and a lower tube at the time of tightening and releasing the adjusting lever for a tilt or telescope operation, so that the steering column can be prevented from being deformed or damaged when a driver operates a steering wheel. The present invention also relates to a steering apparatus for a vehicle having the above-mentioned steering column.
2. Description of the Prior Art
As generally known in the art, a steering column for a vehicle is an apparatus that is formed to enclose a steering shaft for transmitting a torque produced when a driver rotates a steering wheel to a rack-and-pinion mechanism so as to support the rotation of the steering shaft, in which the steering column is coupled to the vehicle body through a bracket so as to fix the position of the steering shaft.
Such a steering column may be additionally provided with a telescope or tilt function, in which a tilt apparatus is an apparatus for adjusting the fixing angle of the steering wheel, and a telescope apparatus is formed by fitting two hollow tubes into one another to be axially extendible/retractable so that the steering shaft and the steering column can be collapsed to absorb an impact energy in a vehicle crash.
Accordingly, steering apparatuses may be classified into a telescope type steering apparatus and a tilt type steering apparatus depending on the functions thereof. Occasionally, the tilt function may be added to the telescope type steering apparatus, so that a driver is allowed to adjust the degree of extension or tilt angle of the steering wheel to be suitable for his/her height or body type through the tilt function so as to smoothly conduct the steering operation.
FIG. 1 is an exploded perspective view illustrating a part of a conventional steering column for a vehicle.
As illustrated in FIG. 1, the conventional steering column for a vehicle includes: an upper tube 100 configured to accommodate a steering shaft 175; a lower tube 170 fitted in the upper tube 100; a lower mounting bracket 165 for fixing the lower tube 170 to a vehicle body; an upper mounting bracket 105 installed on the top side of the upper tube 100 and fixed to the vehicle body; a distance bracket 180 fixed integrally with the upper tube 100 and formed with a telescope slot 185; a tilt bracket 150 formed integrally with the upper mounting bracket 105, and formed with an elongated tilt slot 110; a stationary gear 145 formed on the outer surface of the tilt bracket 150; a movable gear 140 configured to be engaged with or disengaged from the stationary gear 145; a tilt bolt 130 extending through the tilt slot 110; a cam 135 coupled to the movable gear 140; a washer 125 and a nut 120 configured to fix the cam 135 and an adjusting lever 115; and a gear spring 142 positioned between the movable gear 140 and the stationary gear 145.
Both the tilt and telescope operations are applied by tightening or releasing the adjusting lever 115. When the adjusting lever 115 is tightened, the tilt bracket 150 is narrowed to apply a compressive force to the upper tube 100, so that the upper tube 100 and the lower tube 170 can be tightly contacted with each other to disenable the tilt and telescope operations. To the contrary, when the adjusting lever 115 is released, the compressive force disappears from the upper tube 100 and the lower tube 170 to enable the tilt and telescope operations.
The telescope operation is completed by releasing the adjusting lever 115, then changing the position of the tilt bolt 130 along the telescope slot 185 formed in the distance bracket 180, and then tightening the adjusting lever 115.
The tilt operation is completed by releasing the adjusting lever 115, then changing the tilt bolt 130 along the tilt slot 110, and then tightening the adjusting lever 115.
In the state in which the adjusting lever 115 is locked, the upper tube 100 and the steering shaft 175 are fixed. When the adjusting lever 115 is released, the upper tube 100 and the lower tube 170 may be tilted in relation to a tilt center 160 or the steering column may be extended or retracted axially by the cam 135.
Such a conventional steering column for a vehicle has a problem in that a column bearing force and rigidity of the column itself are poor since loads are concentrated to the tilt bracket and the distance bracket that tighten the steering column with the tilt bolt and the adjusting lever.
Specifically, there are problems in that since a connection part between the upper tube and the tilt bracket fixed to the vehicle body through the upper mounting bracket is fragile, the rigidity of the column itself is reduced as compared to the column bearing force so that the steering column may be deformed or damaged by a torsional load produced when the driver operates the steering wheel, and a substantial bending may occur in a vehicle crash.